Jon,
on some Chevy radios the extra wire for the dial light may not be present anymore. That is because the replacement on/off switches sometimes came with only one switch. Thus a previous repair may have eliminated the second wire for the dialight. In this case the dial light would come on whenever the radio is turned on.
If you open it up, you will see some clues as to the function of the two wires. One of them will lead to the area of the power switch and the speaker lead will lead to a small transformer for the speaker output. Also, if you connect an ohm meter between one of the wires and ground, you should get more information. On the power lead, you will probably see a reading of infinity when the power switch is off and a low reading when it is on. This will depend on the health of the vibrator in the power supply. If the other wire is the speaker wire, you should get a steady reading of maybe a few hundred ohms regardless of the off and on switch.
Fred
Last edited by truckernix; 06/27/2008 11:24 AM.